Gun perforator device



March 21, 1944. Q KEPLINGER 2,344,778

GUN PERFORATOR DEVICE Filed Feb. 9, 1943 1 l WW 5 h w M mwl k wwwwwwwvw3 MMWWWWWW Fig. I Fig. 2

lnv znror: Charks H. kz plinqer PatentedMar. 21, 1 944 GUN PERFOBATORDEVICE Charles H. Keplinger, Centralia, 111., assignor to ShellDevelopment Company, San Francisco, Calif., a corporation of DelawareApplication February 9, 1943, Serial No. 475,302

, 5 Claims.

This invention pertains to the operation of gun perforators in oil andgas wells, and relates more particularly to a device for catching andretrieving gun perforator bullets or projectiles which fail to penetratethe casing, whereby the effectiveness of the shooting operations may beascertained.

In perforating a casing by means of a gun perforator, a housing mountinga desired, usual- 1y fairly large, number of loaded barrels, is loweredinto a well to a desired level, and the barrels are caused todischarge-their projectiles into the casing for the purpose ofestablishing fluid communication between the interior of the well andthe surrounding formations.

It sometimes lfiippens, however, that, due to the high temperaturesprevailing in wells, and to the jarring shocks to which the gunperfcrator is subiected while being moved in a well, one or severalprojectiles are prematurely discharged before the gun perforator isplaced at the proper level.

It also sometimes happens that the bullets or projectiles fail, forvarious reasons, to penetrate the casing, but glance off said casing andfall to the bottom of the well. These bullets may sometimes be lateraccidentally retrieved at the surface, for example, during bailingoperations.

It is, of course, of considerable importance to determine theeffectiveness of a gun perforating operation, that is, the ratio of thenumber of bulletswhich actually penetrate the casing to the number ofbullets which fail to do so.

Furthermore, during the process of completing or recompleting a well,several gun perforating operations may be carried out at different timesand/or different levels in the well. In such cases, it is also ofconsiderable importance to determine the effectiveness of each of saidseparate perforating operations.

It is, therefore, an object of this invention to provide a device forcatching and retrieving gun perforator bullets which fail topenetratethe cas-' ing. from which, linowingthe total number of bulletsdischarged, the effectiveness of the perfo-f rating operations may bedetermined or esti-' mated.

It is also an object of this invention to provid for the above purpose adevice that is readily adapted to be mounted upon the bcttompf the gunperforator, and that will travel along to,

gether therewith without creating undue stresses on the hoisting cabledue. to friction either'with the walls of the-well or the fluid standinginsaid well. 7 It'is also an object'oi this invention to provide for theabove purpose a device adapted to retrieve all bullets failing topenetrate the casing of a well, either prematurely fired, or fired atone or more desired levels, and to diiferentiate be-' tween saidbullets.

These and other objects of this invention will .be understood from thefollowing description,

section, of the gun perforator bullet catcher device of the presentinvention; and

Fig. 2 is a diagrammatic sketch of a somewhat v modified embodiment ofthe device of Fig. 1.

Referring to Fig. 1, a gun perforator housing 3, mounting any desirednumber of gun barrels 4, islowered on a cable 1 into a well ll having acasing 2. 1

Attached to the bottom of the housing 3 by any suitable means is ametallic stem 8, supporting a container 9, which may be made of ametallic or plastic material. The container 9 is constructed withcircular or cylindrical walls fitting reasonably closely within thewalls of the well. and has preferably a spherical bottom porton providedwith perforations H) to eliminate swabbing eflects when the apparatus ismoved through the well fluid.

An apron I, made of rubber, rubberized canvas. or of any other desiredresilient material, is affixed to the upper rim of the container 9, andflares upwardly so as to have its upper edge substantially in contactwith the well casing. Metallic plates 6, which may be, for example, bentover the upper edge of the apron l and affixed thereto; may be used toreinforce said edge.

When the gun perforator, together with present bullet catcher, is beinglowered into the well.

the fluid passes easily upwards through the perforations l0 and aroundthe edges of the resilient apron 1.

Upon reaching the desired an in the well, the

tained, the perforations It being of sufllciently, .small size toprevent the bullets from passing therethrough.

After-the completion of the to give way upon meeting such obstruction(as well as obstructions of other types which may be encountered in thewall) whereby the danger of'tne apparatusbecoming stuck or lost in'thewelliseliminated: The metallic plates 6 reinforcing the edge of theapronl exert a scraping action on the casing, whereby any bullets whichare not embedded too'fi'rmly in the casing, are

gun perforating operations, the whole apparatus is pulled to the.surface by means of the cable I. The bullets which neither perforatedthe casing, nor reibounded therefrom, but remained embedded in saidcasing, partially sticking out into the well bore, do not serve as anobstacle to the raising operation, since the apron '1 is sufiicientlyfiexible scraped out and caused to fall into the bullet catcher.

Incases where it is desired to ascertain whether any bullets which hadfailed. to .penetrate the casing had been fired prematurely, a somewhatmodified embodiment of the present catcher, shown in Fig. 2, may beused. This embodiment can also be advantageously used in cases when twodifferent zones are to be perforated consecutively without raising theperforator to the surface, and the effectiveness of each separateperforating job is to be determined from the number of bullets failingto penetrate the formation in each case. V v

The bullet catcher of Fig. 2 is similar to that of Fig. 1, except thatthe stem 8, supporting the receptacle 1 is slidably surrounded by asleeve 12, which carries guide spring members I3 in frictionalengagement with the casing 2. v

A perforated cover plate 15, adapted to fit within the receptacle 1,wherein it may rest, for example, against an annular or segmental stopmember l8, has a central elliptical or elongated opening I6, whichpermits said plate to be carried in a slanted position around the stem8.

This cover plate may be supported from the sleeve I! by means of a tripcatch l4, while a leaf spring l1 may be used to maintain it in thedesired slantingposition and to guide it within the receptacle I.

When the gun perforator is being lowered into the well, the weight ofthe perforator casing, acting through the stem 8, forces the receptacleI downwards in rigid space relationship to said housing. At the sametime, the friction of the guide springs I3 against the casing 2 causesthe sleeve [2 to assume its uppermost position on the stem 8. The deviceis therefore in the condition shown in Fig. 2, and any bulletsprematurely fired at this time, which fail to penetrate the casing, fallpast the slanting cover plate I! and are collected in the bottom of thereceptacle I, below the stop- It.

When the zone of the well which it is desired to perforate is reached, apull is applied to the cable, slightly raising the housing 3, stem I andreceptacle 1. The sleeve l2,however, tends to remain substantiallystationary due to the friction of the guide springs l3 against thecasing.

The sleeve 12, together with the cover plate I5 carried thereby,descends therefore with regard to the stem 8. until the lower end ofsaid plate, guided by the spring 11, comes to rest within thecontainer 1. This causes the trip catch H to release the cover plate 15,which falls within the receptacle I and assumes a horizontal position,being supported by the stop member l8. Any bullets fired subsequent tothis and failing to penetrate the casing, fall, of course, on top ofsaid plate, and are segregated from previously fired bullets.

The same procedure applies to the case when two zones are consecutivelyperforated by the same perforator without raising the latter to thesurface. In such cases, the first zone is perforated without releasingthe cover plate' l5, while the second is perforated after releasing saidplate, whereby the number of failures occurring during each operationcan be easily ascertained.

It is obvious that the scheme described above for releasing the plate I!can be modified in any desired mechanical details to secure the effectof the change of position of a cover plate for abullet catcher from aninoperative to an operative position.

It is also understood that, although the present invention has beendescribed with regard to operations in cased wells, it is equallyapplicable to uncased wells wherein the use of a gun perforator isdesirable in connection with purposes such as acidizing, increase ofproduction, scouring of side-wall samples, etc.

I claim as my invention:

1. The combination of a gun perforator adapted to be lowered into a wellon a cable and to discharge projectiles into the walls of the well, anda bullet catcher adapted to receive the bullets which fail to penetratethe walls of the well and fall down by gravity, said bullet catchercomprising a receptacle having an open upper face and aperioratedbottom. said receptacle being positioned below said gunperforator and. attached thereto.

2. The combination of a gun perforator adapted 'to be lowered into awell on a cable and to discharge projectiles into the walls of the welland a bullet catcher adapted to receive the bullets which fail topenetrate the walls of the well and fall down by gravity, said bulletcatcher comprising a receptacle having cylindrical walls adapted to fitclosely within the walls of the well, an open upper face and aperforatedlower face, said receptacle being positioned below said gun perforatorand attached thereto.

3. The combination of a gun perforator adapted to be lowered into a wellon a cable and to discharge projectiles into the walls of the well, anda bullet catcher adapted to receive the bullets which fail to penetratethe walls of the well and fall down by gravity, said bullet catchercomprising a receptacle having cylindrical walls, a resilient annularmember afiiixed thereto for close sliding contact with the walls of thewell, an open upper face and a perforated lower face, said receptaclebeing positioned below said gun perforator and attached thereto.

4. The combination of a gun perforator adapted to be lowermi into a wellon a cable and to discharge projectiles into the walls of the well, anda bullet catcher adapted to receive the bullets which fail to penetratethe walls of the well and fall down by gravity, said bullet catchercomprising a receptacle having an open upper face, a perforated bottom,a perforated cover plate on said receptacle adapted to close said upperface, said cover plate being normally carried in an inoperative openposition, and means operable through the cable supporting the gunperforator for shifting said plate to an operative closed position, saidreceptacle being positioned below said gun perforator and attachedthereto.

5. The combination of a gun perforator adapted to be lowered into a wellfor discharging projectiles into the walls of the well from a pluralityof gun barrels, and a bullet catcher attached to said perforator belowsaid barrels, said bullet catcher comprising an upwardly openingreceptacle adapted to retain the projectiles which fail to penetrate thewalls of the well and fall down by gravity.

CHARLES H. KEPLINGER.

